Support more swizzles to 565 in SkCodec

tests/CodexTest.cpp

Index: tests/CodexTest.cpp
diff --git a/tests/CodexTest.cpp b/tests/CodexTest.cpp
index 95cd5635445ca6fa62dd378c7893e46ad58a0996..80164b294bbc03faf31dcbc2877b78582e5a4d60 100644
--- a/tests/CodexTest.cpp
+++ b/tests/CodexTest.cpp
@@ -78,7 +78,8 @@ static void check(skiatest::Reporter* r,
                   const char path[],
                   SkISize size,
                   bool supportsScanlineDecoding,
-                  bool supportsSubsetDecoding) {
+                  bool supportsSubsetDecoding,
+                  bool supports565 = true) {

[scroggo, 2015/08/13 18:09:43]

This feels like a bit of a hack. I had assumed that we could always decode to
565, but it turns out we cannot for CMYK. It seems like we could use the
swizzler to get 565, once Emmalee's change goes in that uses the swizzler in
JPEG for sampling.

[msarett, 2015/08/13 18:16:17]

Agreed, however I feel fine about this.  I'm not really thrilled with how we
support CMYK to RGBA either.  Improving CMYK->RGB formats is a TODO for me. 
Feel free to add a TODO (msarett) here to fix this.

     SkAutoTDelete<SkStream> stream(resource(path));
     if (!stream) {
         SkDebugf("Missing resource '%s'\n", path);
@@ -96,6 +97,15 @@ static void check(skiatest::Reporter* r,
     // decodes to all possible destination color types.
     SkImageInfo info = codec->getInfo().makeColorType(kN32_SkColorType);
     REPORTER_ASSERT(r, info.dimensions() == size);
+
+    {
+        // Test decoding to 565
+        SkImageInfo info565 = info.makeColorType(kRGB_565_SkColorType);
+        SkCodec::Result expected = (supports565 && info.alphaType() == kOpaque_SkAlphaType) ?
+                SkCodec::kSuccess : SkCodec::kInvalidConversion;
+        test_info(r, codec, info565, expected, NULL);
+    }
+
     SkBitmap bm;
     bm.allocPixels(info);
     SkAutoLockPixels autoLockPixels(bm);
@@ -213,7 +223,7 @@ DEF_TEST(Codec, r) {
     check(r, "randPixels.gif", SkISize::Make(8, 8), false, false);
 
     // JPG
-    check(r, "CMYK.jpg", SkISize::Make(642, 516), true, false);
+    check(r, "CMYK.jpg", SkISize::Make(642, 516), true, false, false);
     check(r, "color_wheel.jpg", SkISize::Make(128, 128), true, false);
     check(r, "grayscale.jpg", SkISize::Make(128, 128), true, false);
     check(r, "mandrill_512_q075.jpg", SkISize::Make(512, 512), true, false);